Connor Bates, portrayed by Ray Nicholson, is a young man grappling with a tumultuous past, living in the confines of his mother's basement in a quaint yet stifling coastal town in Rhode Island. To make ends meet, he works at the local library, a place he feels fortunate to be employed given his criminal record, which stemmed from a three-year prison sentence for an assault charge. His day-to-day existence involves navigating the complex aisles of books, all while withstanding the relentless scorn of his probation officer, [Jock](hank-azaria) (Hank Azaria), who seems particularly intent on berating him over every minor infraction, including lateness. However, amidst these challenges, Connor finds solace in his passion for jogging, utilizing the scenic coastal paths to run off his pent-up emotions.
Everything changes one fateful morning when he encounters a striking woman named [Marilyn](diane-kruger) (Diane Kruger), who captivates him in a vibrant red swimsuit. Their flirtation is immediate and electric, setting the tone for a burgeoning connection. A few days later, Marilyn pays a visit to the library, concealing a bruise behind dark sunglasses, which she claims occurred at the hands of her husband, [Richard](victor-slezak) (Victor Slezak). In a twist of fate, she requests books on crime and murder, at which point Connor recommends the novel, The Postman Always Rings Twice, a tale about a drifter ensnared by a wealthy older woman into committing an unthinkable act. As Marilyn departs, she leaves behind her home phone number, tucked inside a dollar bill – an invitation Connor cannot resist.
Invigorated by their conversation, Connor makes the call, which subsequently leads to a series of clandestine meetings where Marilyn reveals the dark truth about her life. She shares the harrowing details of her abusive marriage to Richard and the impact it has on her teenage stepdaughter, [Astrid](chase-sui-wonders) (Chase Sui Wonders). Each encounter deepens their connection, with the sexual tension escalating into an undeniable affair. Meanwhile, Connor's colleague at the library, Kim, hints at Astrid's relationship with the local playboy, Jared ([KeiLyn Durrel Jones]), creating a web of intertwining lives.
As their relationship intensifies, Connor becomes increasingly protective of Marilyn and Astrid, igniting a dangerous desire to rescue them from Richard's oppressive grasp. In a moment of impulsive passion, Connor vows to take matters into his own hands, assuring Marilyn he will kill her husband. They devise a plan: Marilyn and Astrid will take a trip on Richard's yacht, while Connor confronts Richard at their home. While Connor manages to set the plan in motion, the confrontation does not play out as smoothly as anticipated.
In a desperate struggle, Connor finds himself disarmed by Richard, who almost ends his life. Just then, another unexpected assailant intervenes — Jared, who mistakenly believes he's there for a burglary job. Each believing the other poses a threat, chaos ensues, and in a fit of confusion, Connor kills Jared. Following the violent aftermath, Connor receives a call from Marilyn, expressing doubt about her earlier claims and raising suspicions of betrayal. Days pass and the tension builds until Connor receives an urgent message to meet Marilyn, only to be ambushed by police, including Jock, who have a warrant for his arrest.
What follows is a gripping chase, culminating in a tragic confrontation where Connor realizes too late that he has been set up as the scapegoat for Marilyn's deeds. A miscommunication with the police leads to his untimely demise, as they mistake his reach for his phone as a threat. Connor's last moments are haunted by the haunting vision of Marilyn in her red swimsuit, a stark reminder of how he was drawn into a deadly web of deceit.
In a chilling twist, the narrative shifts as Marilyn and Astrid revel in their victory on a private yacht, their true intentions exposed. They whisper about a library book that Marilyn had checked out — The Postman Always Rings Twice. It's a grim revelation that their entire plan hinged on manipulating Connor, a man with a fragile state of mind, to do their bidding. The two women share a kiss, signaling their mutual feelings for one another, and it becomes evident that Marilyn’s marriage was merely a façade for their deceitful plot to eliminate Richard and claim his riches. With the completion of their sinister scheme, Marilyn looks to Astrid and assures her that nothing can ever come between them again.
